Cleaning cassette

ABSTRACT

A cleaning cassette for cleaning the heads of streamer tape drives has a wiper arm (14) carrying a foam wiping pad (40) at one end and pivoted in the casing (12) at the other. A pick-up wheel (60) engages the capstan of the drive and reciprocates the wiper arm, through gear wheels (62,26) and a crank arm (30), to cause arcuate movement of the pad across the head. The pad has a thicker central portion (44) and thinner wings (46), and a metal base strip (42) is compressed over the wings. Effective head cleaning is achieved in a simple and practical structure without excessive head wear.

BACKGROUND OF THE INVENTION

The present invention provides an apparatus for cleaning therecord/playback head of a cassette drive device such as a magnetic tapedrive device, the apparatus having a casing in the form of a cassettewhich may be inserted into the cassette drive device.

The invention is particularly concerned with streamer tape drives, asused for back-up purposes in computer installations. U.S. Pat. No.4,631,614 discloses in FIG. 6 a cleaner for the heads of a streamer tapedrive in which a complex drive train transmits drive to a rockingcleaning head which wipes a pad across the heads in a directiontransverse to the direction of tape movement (or the longitudinal extentof the tape). Other head cleaning proposals include European PatentApplication No. 0 188 655 which is a purely manual streamer tape drivehead cleaning system, and U.S. Pat. Nos. 4,442,468; 4,149,206 and3,955,214 which describe cleaners for audio tape cassette drives ofwell-known type in which a cleaning means is driven from the usualsprocket or hub of the cassette. We have found that none of thesesystems are satisfactory for streamer tape drives in providingsufficient cleaning action without causing undue wear on the heads.

SUMMARY OF THE INVENTION

The present invention is defined in the appended claims to whichreference should now be made for a definition thereof.

A particularly preferred example of the invention takes the form of acleaning cassette having a casing and containing a wiper arm pivoted inthe casing at one end and at the other end carrying a replaceable wiperpad assembly which follows an arcuate path on pivotal movement of thewiper arm. The wiper arm is driven from the capstan drive wheel of thedrive the heads of which are being cleaned through a pick-up wheel whichcontacts the capstan drive wheel when the cleaning cassette is in use.The pick-up wheel drives a large wheel through toothed gearing and acrank arm is eccentrically pivoted by one end on the large wheel. Theother end of the crank arm is attached to the wiper arm to drive thesame.

The replaceable wiper pad assembly is slidable into a T-socket on thewiper arm and includes a pad having a thicker central portion andopposed thinner planar wings. A metal base plate is crimped over thewings.

It is an advantage of the head cleaning cassette of the presentinvention that it can be loaded into a magnetic tape drive device in thesame way as a magnetic tape cassette is loaded. A further advantage isthat the cassette is operated by the tape drive to simply andeffectively clean the head.

BRIEF DESCRIPTION OF THE DRAWINGS

Cleaning cassettes embodying the invention will now be described indetail, by way of example only, with reference to the accompanyingdrawings, in which:

FIG. 1 is a schematic plan view of a cleaning cassette in accordancewith this invention;

FIG. 2 is a sectional view taken on the line II--II in FIG. 1 showingthe gear drive;

FIG. 3 is a sectional view taken on the line III--III in FIG. 1 showingthe wiper arm;

FIG. 4 is a view of the wiper head;

FIG. 5 shows the wiper head in a partially-assembled condition;

FIG. 6 is a view similar to FIG. 4 of a possible modification of thewiper head;

FIG. 7 is a detail view showing a capstan cleaning pad;

FIG 8 is a section taken on line VIII--VIII in FIG. 7; and

FIG. 9 is a view similar to FIG. 1 of a slightly modified head cleaningcassette.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIGS. 1 to 3, the cleaning cassette 10 has a casing 12designed to be suitable for loading into a magnetic tape drive device or"streamer" tape such as commonly used for back-up purposes in computerinstallations. As the external shape of the casing 12 is of standardtype, it is not described here in detail; it will be seen that it has athickness substantially less than its width and length to present agenerally planar configuration. A typical size is approximately 150 mmby 100 mm by 16 mm. The casing houses a wiper arm 14 movable in theplane of the casing about a pivot 16 formed on the casing. The head endremote from the pivot 16 is formed with a T-slot 18 to receive a wiperpad, as described below.

To provide drive to the wiper arm, a pick-up wheel 20 frictionallyengages with the capstan drive wheel (not shown) of a cassette tapedrive in conventional manner. The pick-up wheel 20 is mounted coaxiallywith a first toothed gear 22 which engages an idler gear 24 which inturn engages a larger gear 26. The large gear 26 operates as a cam wheeland to that end has an eccentric bush boss or 28 on its upper surfaceover which is mounted a crank arm 30 with a corresponding aperture 32 atone end. The crank arm 30 is linked to the middle portion of the wiperarm at its other end by a rivet portion 34.

In use, the cassette is loaded into a magnetic tape drive device in thenormal way. When the tape drive is started, the capstan drive wheeldrives the pick-up wheel 20 which rotates the cam wheel 26 through thegear train 22,24. The gear train provides a reduction of between 2:1 and10:1, preferably around 5:1. The rotation of the cam wheel 26 thencauses the crank arm 30 to reciprocate the wiper arm 14 so that the headend of the wiper arm carrying the wiper pad moves back and forth acrossthe head to be cleaned, generally in the direction of tape movement,namely as shown by the double headed arrow A.

The toothed gear drive could be replaced by a frictional drive couplingas an alternative.

The arcuate path for the cleaning head has the advantage that maximumcleaning pressure is applied to clean the drive head over its centralregion where the build-up of dirt may be greatest. This we have found tobe particularly effective in removing contaminant while tending tominimise wear on the heads. The cassette illustrated thus provides aself-contained automatic head cleaning apparatus in a simple and compactform. Provision may be made in the casing for the introduction of acleaning solvent to improve the cleaning efficiency of the pad(s).

It should be noted that the cassette is simple to make and that thebushings and mountings for the various components are made byappropriate shaping of the base and top plates as shown.

The cleaning pad assembly will now be described with reference to FIGS.4 and 5. The pad assembly comprises a pre-formed foam element 40 and analuminum strip 42. As shown in FIG. 5, the preshaped foam elements has asolid thicker central portion 44 and two thinner wings 46. The aluminiumstrip forms a base for the pad and has two flanges 48 which are foldedover to compress the wings 46 and thereby secure the foam element 40.The aluminium base can then be slid only the T-slot 18 at the top of thewiper arm 14. The pad is thus easily replaceable when it becomes soiled.In a modification of the head 18 as shown in FIG. 6, the head is curvedand receives a correspondingly curved pad assembly.

The foam pad 40 is shaped so that as it passes across the head it candistort sideways as shown by the dashed lines B in FIG. 4. This we havefound to be particularly effective in achieving good cleaning withoutundue wear on the heads, especially when considered together with thearcuate path transversed by the pad.

Other advantageous features may be added to the cassette describedabove. For example, it may be desirable to include in the casing astatic pad arranged to come into contact with the capstan drive wheel soas to provide a cleaning action as the capstan rotates. Such a staticfoam pad 50 is shown in FIG. 7 and 8 and is mounted in a moulding 52 inthe casing so as to project against the surface of the capstan drivewheel 54. The pad 50 is held in a U-shaped aluminum strip retained in aslot 56 in the moulding 52.

The modification of FIG. 9 is similar in principle to the cleaner ofFIG. 1 and will not therefore be described again in detail. In this casehowever the idler gear 24 is omitted. The pick-up wheel 60 is largerthan the pick-up wheel 20 and frictionally engages with the capstandrive wheel. The pick-up wheel 60 is mounted coaxially with a toothedgear 62 which engages directly with the gear 26. As with FIG. 1,rotation of the pick-up wheel is converted to arcuate reciprocation ofthe wiper pad 40 against the head 64 to be cleaned, the reciprocationbeing in the direction parallel to the direction of movement of the tapein a standard cassette. The overall size of the casing 12 in this caseis approximately 80 mm by 60 mm.

Certain drives have photocell/lamp combinations to detect the beginningand end of tape of a standard cassette. It may be necessary to includeone or more opaquing plates 68 in the cleaning cassette located tointerrupt the light from the lamp so that it does not reach thephotocell. Otherwise the tape drive may switch off automatically, as itapparently senses that the end of tape has been reached.

Many modifications may be made to the arrangements illustrated withinthe scope of the invention as defined in the following claims.

I claim:
 1. A cleaning cassette for cleaning a record/playback head of acassette drive device, said cassette comprising:a casing having athickness substantially less than its width, said casing presenting agenerally planar configuration; a head wiping element; a wiper armhaving first and second ends, said first end of said wiper arm beingsupported in said casing by pivotal support means for angular movementof said wiper arm about a first axis perpendicular to said generallyplanar configuration, said second end of said wiper arm carrying saidhead wiper element for arcuate movement in a direction of tape travel; apick-up wheel having means for facilitating rotational driving of saidpick-up wheel by a capstan drive wheel of a cassette drive device, saidpick-up wheel being supported in said cassette for rotation about asecond axis generally parallel to said first axis; a further wheelsupported in said cassette for rotation about a third axis generallyparallel to said second axis and having an eccentric portion; couplingmeans for interconnecting said pick-up and further wheels so thatrotation of said pick-up wheel causes rotation of said further wheel;and a crank link having a first end pivotally supported on saideccentric portion of said further wheel, and having a second endpivotally supported on said wiper arm at a position between said firstand second ends of said wiper arm.
 2. A cassette according to claim 1,wherein said eccentric portion of said further wheel is an eccentricboss, and wherein said first end of said crank link has an aperturewhich recieves said eccentric boss on said further wheel.
 3. A cassetteaccording to claim 1, wherein said coupling means provides a reductionratio between said pick-up wheel and said further wheel which is inexcess of 2:1.
 4. A cassette according to claim 3, wherein saidreduction ratio is about 5:1.
 5. A cassette according to claim 1,wherein said coupling means including said further wheel having atoothed gear portion, and includes a toothed gear coaxially mounted withsaid pick-up wheel in said casing.
 6. A cassette according to claim 5,wherein said coupling means including an idler gear engaged with saidtoothed gear and with said toothed gear portion of said further wheel.7. A cassette according to claim 1, including a static pad located tocontact a capstan drive wheel of a cassette drive device so as toprovide a cleaning action as the capstan drive wheel rotates.
 8. Acassette according to claim 1, including opaquing means on the casinglocated to interrupt a light path between a lamp and a photocell of atape detector in a drive.
 9. A cassette according to claim 1, whereinsaid wiper element includes a foam pad having a thick central portionand two opposed thinner wings, and includes a metal base strip havingflanges bent over and compressing the wings to secure the pad thereto.10. A cleaning cassette for cleaning the record/playback head of acassette drive device, comprising a casing having a thicknesssubstantially less than its width to present a generally planarconfiguration; a wiper arm which has first and second ends, which ispivotally mounted at the first end within the casing so as to be movablein the plane of the casing, and which carries a wiping element at thesecond end for arcuate movement across a drive head; a pick-up wheelsupported in the cassette to engage a capstan drive wheel of a drive;and means for drivingly coupling the pick-up wheel to the wiper arm soas to reciprocate the wiper arm in response to rotation of the pick-upwheel, the reciprocation of the wiper arm causing the wiping element tomove generally in a direction of tape movement across the head; in whichthe coupling means includes a crank arm having first and second ends andincludes a second wheel driven from the pick-up wheel, the second wheelhaving an eccentric pivot mounting which is engaged by the first end ofthe crank arm, the second end of the crank arm being pivotally coupledto an intermediate portion of the wiper arm; and in which the couplingmeans provides a reduction ratio between the pick-up wheel and thesecond wheel in excess of 2:1.
 11. A cassette according to claim 10, inwhich the reduction ratio is about 5:1.
 12. A cleaning cassette forcleaning the record/playback head of a cassette drive device, comprisinga casing having a thickness substantially less than its width to presenta generally planar configuration; a wiper arm which has first and secondends, which is pivotally mounted at the first end within the casing soas to be movable in the planar of the casing, and which carries a wipingelement at the second end for arcuate movement across a drive head; apick-up wheel supported in the cassette to engage a capstan drive wheelof a drive; and means for drivingly coupling the pick-up wheel to thewiper arm so as to reciprocate the wiper arm in response to rotation ofthe pick-up wheel, the reciprocation of the wiper arm causing the wipingelement to move generally in a direction of tape movement across thehead; in which the coupling means includes a crank arm having first andsecond ends and includes a second wheel driven from the pick-up wheel,the second wheel having an eccentric pivot mounting which is engaged bythe first end of the crank arm, the second end of the crank arm beingpivotally coupled to an intermediate portion of the wiper arm; in whichthe second wheel has a toothed gear portion, the coupling means includesa toothed gear coaxially mounted with the pick-up wheel in the casing,and in which the coupling means includes an idler gear engaged betweenthe toothed gear and the toothed gear portion of the second wheel.